Chemical sampling and multi-function detection methods and apparatus

ABSTRACT

This invention describes a sample collection method that could release and collect residues of explosives and other chemicals from a surface; the described method is implemented into a compact detection system that can be used as a “wand” for screening chemicals residues on human body. The wand configuration includes multiple functionalities for contrabands detection. The invention further describes a desorption method that can control chemical fragmentation pathway during desorption. The invention describes a combined detection device that detects trace chemicals and metal at the same time.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/736,233, filed Apr. 17, 2007, the entire content of which is hereinincorporated by reference. The present application claims the benefit ofand priority to corresponding U.S. Provisional Patent Application No.60/767494, filed Apr. 18, 2006, the entire content of which is hereinincorporated by reference.

BACKGROUND OF THE INVENTION

Increasingly, explosives and other chemical warfare agents have becomeparamount threats to screen for in airports and government buildings.With access to plastic explosives and skillful disguising of weapons andexplosive devices as ordinary, innocuous objects, terrorists need to beidentified from the general passengers boarding aircraft or enteringgovernment buildings. It is known that certain explosive materials areinherently sticky, such as C-4 (a RDX based explosive) and can beremoved from luggage or objects by physically touching (wiping) asampling trap across the surface and then inserting the sampling trap ina detector such as an ion mobility spectrometer for analysis. Screeningof people is a more difficult challenge since the above screeningtechnique used on luggage is too intrusive and may violate human rights.A more socially acceptable screening method is to collect the chemicalparticle or vapor on a sampling trap without contacting the person.

By deploying the trace detection portal systems into airport checkpoints, non-contact detection of explosives from airline passengers hasgradually become possible. Currently, the trace detection portal systemsare under some pressure to improve the efficiency of dislodging andcollecting explosive particles from human body. In this invention, wedescribe a sample collection/detection method that could release andcollect residues of explosives and other chemicals more effectively.Instead of using a large scale air handling system to release, collect,transport samples to the detection system as those used in tracedetection portals, a sampling system in close proximity to the targetarea such as a handheld “wand” is described herein for screeningchemical residues on the human body.

The concept of a using a handheld “wand” is a well accepted concept atsecurity check points. Handheld metal detectors are still the best wayto search for weapons on selectees when they cause an alarm at thewalkthrough metal detector. This invention describes a handheld wandthat can be used to confirm an alarm from the trace detection portalsystems. In addition, flexibility and portability of the handheld wandwill extend its application to broader security related areas,especially where a trace detection portal is not available. The handheldwand can be used as an intermediate step before a complete manual searchis performed. Additionally, the handheld wand can be combined withmultiple detectors for searching multiple threats. An exhaustive searchfor multiple threats can save valuable time and effort.

SUMMARY OF THE INVENTION

When a terrorist prepares explosive devices, trace amounts of theexplosive inevitably clings to the person's skin and/or clothing. Anadvantage to performing a search with a handheld wand over detectionportal systems is the ability to position the wand over a desirablelocation on the individual. This is contrary to the detection portalsystems where the air jets are in a fixed position and screening fordifferent size or height individuals may miss a desirable location onthe individual. In addition, another advantage to performing a searchwith a handheld wand over detection portal systems is the process ofcollecting the particles. Since the collector is closer to the air jetsin the handheld wand, the explosive particles and/or vapor is collectedmore effectively. This close proximity is also advantageous for otherdetecting devices that can be incorporated into the handheld wand, suchas a metal detector or a Geiger counter.

The handheld wand can have many different configurations. The firsthaving a sampling component, for sampling and preconcentration ofchemicals in both particle and vapor form. This sampling configurationwill allow for collecting explosives onto media such as a samplecollector that is compatible with the current trace detection systems.The samples collected from the wand on the sample collector could bedirectly inserted into a detection system. Secondly, a configurationwhereby the handheld wand is integrated with an onboard ion mobilitybased detector or other detection method, without significantlyincreasing the size and weight, could be optimized to detect explosivesand other chemicals with higher systemic sensitivity compared to theportal systems. The handheld wand can be a rugged, battery operateddetector that is intended to be used in the same fashion as the handheldmetal detectors. Thirdly, a configuration where the handheld wand isused as a single device to search for multiple threats by combining thechemical sampling and/or detection components with other detectors toprovide a multi-function detection wand.

This invention describes a dynamic inspection method that enables directsampling of particles and/or vapors on the human body or other surfaces.The described chemical sampling and detection method is capable ofreleasing and extracting particles and vapors from the cloth,preconcentrating these samples in the wand, and/or detecting them in afew seconds with the onboard detection method, e.g. ion mobilityspectrometer (IMS). It uses an air pump or pumps to generate bothimpinging and collecting air flows. Continuous or pulsed air jets arecombined with adjacent suction ports to release and collect particlesfrom clothing. In addition, with the handheld wand configuration, vaporscan also be collected from the inner layer of the fabrics. Used in aclose range from targeted samples, the handheld wand should have abetter sample collection efficiency compared to the portal systems. Thecapability of being able to detect vapors under the clothing may addressdifferent kind threats that are not well detected by trace detectionportals, i.e. a well packed hidden bulk amount of chemicals, such asexplosives, on human body. As for explosive detection, most explosivesdo not have a very high vapor pressure to be detected in an open area,however, under one or multiple layers of clothing, the vapor pressurecould reach a detectable range, especially, when the bulk materials areheated by body heat. Assuming the body temperature (.about.37.degree.C.) is ten degrees above the environment temperature, the vapor pressureof explosives may increase 5 to 15 times [Yinon, Jehuda, Forensic andEnvironmental Detection of Explosives, John Wiley, Chichester, 1999].

Several approaches for screening people and/or objects have beendeveloped in the past that involve collecting explosive particles and/orvapor using portable/handheld devices, however, they either contact thesubject, or are not suitable for screening large surface areas rapidly,such as the human body. In order to not violate human rights, the moresocially acceptable screening method is to not contact the person.Unlike the methods of using a handheld device for sampling by contactingthe targeted area, the present invention provides a unique and effectiveway to dislodge and collect the particles in a non-contacting manner.

In addition to releasing particles with only the impinging air flow,since certain explosive materials are inherently sticky, such as C-4 (aRDX based explosive) and Deltasheet (a PETN based explosive), thetemperature of the air flow or the addition of a doping substance intothe airflow will assist in lifting and collecting the chemicals ofinterest. Due to the nature of the explosives and form they areproduced, some explosive molecules are generally greasy substances andare hydrophobic. Methods used to lift and collect the particles ofinterest in this invention are to: (1) vaporize explosive molecules byheating, (2) minimize the explosive molecule electrostatics byincreasing humidity by doping moisture in the air flow, thusneutralizing a charge imbalance or by doping plasma (ionized air) in theair flow, (3) separate the explosive molecule from the matrix byutilizing the intermolecular interactions that are exclusive to theexplosive molecule (ionic interaction, hydrogen bonding, dipole-dipole,and .pi.-.pi.) by doping the air flow with one or more substances, and(4) separate the matrix and explosive molecules from the targetedsurface by doping the air flow with easily collectable substances orparticles.

None of the currently marketed handheld trace detection systems areintended to be used to directly detect explosives on people. They arelimited not only by physical size and weight, but also by theirperformance in terms of, e.g. the false alarm rate. In addition, theconcern of leaking radioactive material is the prohibiting factor forcurrent trace detectors to be used directly on people; a non-radioactiveIMS is one of the key elements for a successful trace detection handheldwand.

One of the technologies that will enable the realization of the handheldmulti-function detection wand is an improved ion mobility spectrometerdesign that can be incorporated into a very compact size. Someadditional requirements that are also necessary are: a ruggedspectrometer, so that the handheld wand will not be too fragile fordaily use; a non-radioactive ionization source, so that there would beno public safety concerns of using the handheld wand on people; animproved resolving power, so that there will not be too many falsealarms that need to be addressed. The ion mobility spectrometer designthat is described by U.S. patent application No. 60/766,825 may meetthese requirements and will fundamentally improve IMS detectioncapability.

Generally a detector can be used in two states. A detector can bepassive, identifying changes in environmental conditions, such as therelease of hazardous airborne chemicals or can be active, searching anundisclosed object for explosive chemicals. Using a single detector,such as a metal detector, to identify a threat has become a commonpractice in airports and government buildings over the last 20 years.However, more recently multiple detectors have been utilized to screenpassengers or baggage for multiple threats since criminal activity(terrorists) has become a greater concern. Portal/examination stationsfor detecting a plurality of threats/agents are documented in the patentart; a handheld multifunction detection wand is first time described inthis invention.

Accordingly, a need remains for a handheld multiple detector wand forsearching multiple threats in close proximity to the targeted area thatis suitable to collect residues of explosives and other chemicals moreeffectively than the portal/examination stations and performs anexhaustive search for multiple threats saving valuable time and effortwhen detection portal/examination stations are not available due tospace constraints.

The handheld multi-function detection wand is an apparatus that candetect more than one different threat in a compact unit by conducting ahuman body search. This device does not just have multiple detectors inorder to identify and confirm the same single threat, instead the deviceperforms an exhaustive search for multiple threats saving valuable timeand effort. For example, a person can be searched for guns (metalobjects) and explosives (e.g. TNT) at the same time with amulti-function detection wand that has a chemical detector and a metaldetector together in one apparatus. More detectors could also be addedsuch as an active circuit detector along with the metal and chemicaldetector to further identify and active bomb device on the same person.

The handheld multi-function detection wand can also be combined not onlywith a metal detector, but with a charge and proximity detector, activecircuit detector, electromagnetic field detector, a radiation detector,a biological warfare agent detector, a radar detector, an x-ray detectoror a remote detector that directly analyzes samples on a targetedsurface such as a optical spectroscopy based detector. Any combinationof these or other detectors not mentioned above for identifying a threatcan be combined with the wand for chemical screening. These detectingdevices can be incorporated into the wand solely or in a combination.These additional detecting devices can also be interchangeable moduleswithin the compact size of the wand so that the handheld multi-functionwand can be custom tailored to a particular application.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects, embodiments, and features of theinventions can be more fully understood from the following descriptionin conjunction with the accompanying drawings. In the drawings likereference characters generally refer to like features and structuralelements throughout the various figures. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the inventions.

FIG. 1 is a conceptual drawing of the handheld sampling interrogatingapparatus.

FIGS. 2A and 2B schematically shows a general design of the handheldmulti-function interrogating apparatus that is compatible with currenttrace detectors. FIG. 2B shows a cross section of the lower chamber withimpinging airflows, the outer return airflows, and the center returnairflow.

FIG. 3 schematically shows the air jet array and sample collection slitsin the front sampling region of the handheld interrogating apparatus.

FIG. 4 schematically shows half of the cross sectional view of the lowerchamber sampling particles from a targeted surface with an airflow.

FIG. 5 is a conceptual drawing of the handheld detection interrogatingapparatus.

FIG. 6A schematically shows the handheld detection interrogatingapparatus with docking station/charger. FIG. 6B schematically shows thedifference between the detection and sampling apparatus.

FIGS. 7A and 7B schematically shows the shape of ion outlets fromionization source. FIG. 7C schematically shows multiple rings on aFaraday ion detector.

FIG. 8 schematically shows an alternative embodiment of samplepreconcentration and desorption where preconcentrator can be made of alayer of coils.

FIG. 9 shows a diagram of communication between the handheld detectioninterrogating apparatus and a remote PDA or computer.

FIG. 10A schematically shows the interrogating apparatus impinging airflow and return flow. FIG. 10B schematically shows the angle ofimpinging air flow. FIG. 10C schematically shows possible air flowconfigurations.

FIG. 11A-C schematically shows the dynamic inspection method, moving aninterrogating apparatus in a non-contacting sweeping motion for vaporand/or particle collection.

FIG. 12 schematically shows a preconcentration trap filter with movablescreen.

FIG. 13 schematically shows the addition of a doping substance into theairflow of the interrogating apparatus.

FIG. 14A-D schematically shows lessening the effects of electrostaticsby adding a doping substance into the sheet-like impinging airflow.

FIG. 15A-B schematically shows the removal and collection by way of aclosed loop air current of explosive particles from matrix by selectiveinteraction with the doping substance.

FIG. 16A-B schematically shows an alcohol group as one of the manyreactive sites on a resin bead that binds to the nitro groupfunctionalities (via hydrogen bonding) that are commonly found inexplosive particles.

FIGS. 17A-B schematically shows a liquid phase doping substance that canremove the matrix and explosive particle together and collect them inthe interrogating apparatus by way of the closed loop air current.

FIGS. 18A-B schematically shows a solid phase doping substance that caninteract with the matrix and explosive particle together and collectthem in the interrogating apparatus by way of the closed loop aircurrent.

FIGS. 19A-B schematically shows a doping substance that has amagnetizable material physically admixed within, or chemically combined.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

In a broad sense, this invention can be viewed as a dynamic inspectionmethod and means for conducting a comprehensive search of selectees orobjects whereby the sampling of a human body or objects occurs using aninterrogating apparatus in a non-contacting sweeping motion whereby oneor more sweeps are performed for a targeted surface area.

In a variety of embodiments, the dynamic inspection method andinterrogating apparatus may be a non-contact multi-functioninterrogating apparatus for detecting a plurality of threats. It shouldbe noted that “threats” as used herein below may be, but is not limitedto, chemicals, biologicals, illicit drugs, weapons, explosives,radioactive materials, or other contraband objects/substances. Inaddition, it should be noted that “a different threat” as used hereinbelow may be, but is not limited to, a different component of the firstthreat and/or an independent threat from the first threat. For example,a pipe bomb's explosive chemical content or chemical residues would bereferred as the first threat and the metal pipe in which the explosivechemical is contained could be referred as a different threat, since themetal pipe is a different component of the first threat. A non-limitingexample of different threat may also be an independent threat from thefirst threat, such as, a metal knife along with an explosive chemicalparticle from a pipe bomb.

Unless otherwise specified in this document the term “jet array” isintended to mean a series discrete openings or continuous openings, suchas but not limited to a series of small holes or long narrow slit thatis suitable to regulate fluids into jet like motion.

Unless otherwise specified in this document the term “particle” isintended to mean chemical and/or biological molecules that are; vapor,droplets, an aerosol, liquid, solid, or any other mobile medium in whichspecific molecules of interest may be transported in air.

Unless otherwise specified in this document the term “ion mobility baseddetector” is intended to mean any device that separates ions based ontheir ion mobilities or mobility differences under the same or differentphysical and chemical conditions and detecting ions after the separationprocess.

Unlike conventional prior art handheld chemical detectors, theinterrogating apparatus (sampling and/or detection) design is forrapidly and effectively screening particles on a given targeted surface.It maximizes the exposed surface area between the interrogatingapparatus and the targeted surface as prior art handheld detectors arecommonly referred as sniffers that only sample chemicals from a narrownozzle-like inlet. The sniffer design is not suitable for fast screeninglarge areas, such as the human body. On the contrary, the interrogatingapparatus described in this invention, uses the largest surface area forsample stimulation and collection on the targeted surface area by movingthe interrogating apparatus in a sweeping motion. Simultaneously, in thesame sweeping motion, other contrabands, such as weapons, can also beinspected. In a variety of embodiments, FIG. 1 is the conceptualschematic of the interrogating apparatus 101 as a handheld wand with aparticle sampling component, a housing for multiple detectors 103 and asample/preconcentrating filter 105. The interrogating apparatus willhave a very similar shape as the commercial metal detection wands. FIG.2A shows the engineering sketch of the device. There are three sections:(1) a handle 201 and a power source 204, (2) a middle section chamberadjoining the handle that encloses the pump or pumps 206, electronics,on-off switch 208, a temperature controller, a sample collector, and alocking and dispensing mechanism 209 for the sample collector, (3) thefront sampling region 212 consisting of an upper and lower chamber thatis parallel to the handle, whereby the upper chamber 214 enclosesimpinging and collecting airflow lines and the lower chamber consists ofjets and intake holes. Also shown is a onboard battery charger 205 witha connection port 207. FIG. 2B shows the cross section 202 of the lowerchamber with the impinging airflows 215, the outer return airflows 216and the center return air flow 218. FIG. 3 provides a detailed viewshowing the air jet array 303 and sample collection slits 305 in thefront sampling region 308 of the handheld sampling wand. A generalrepresentation as shown in FIG. 10A-C of alternative sampling portdesigns which can be used are; having a plurality of facing air jetarrays located around the periphery of the lower chamber of the frontsampling region and a plurality of intake holes are located inside ofthe air jet arrays whereby a impacting sheet-like airflow isadministered to a targeted surface. The jets in the arrays may bedesigned by having different sizes to balance the pressure and releaseof particles at different distances from the handheld wand.

A modularized design philosophy will be applied to the sampling handheldwand configuration. Both impinging ports 303 and sample collection slits305 (as shown in FIG. 3) are connected to the air flow manifold at thefront sampling region 308. The manifold serves as the interface betweenthe air pump and sampling ports. When an application requires it, thefront sampling region containing the lower chamber consisting of jetsand intake holes may be exchanged for different sizes and shapes of airjets and intake holes. The components beyond the manifold interfacecould be swapped with another component that has different arrangementof sampling and collection ports. An application may require that theimpinging and sampling flow have a different balance. For example, ifthe wand is to collect samples in a confined area, such as inside of ajacket, impinging flow pressure may be increase to reach far corners forthe best result, in this case, the front portion of the wand may bereplaced in situ.

In a variety of embodiments, FIG. 10A-C shows the configuration of airjet ports 1015 and intake ports 1018 are such that the air jet portsthat dislodge chemical vapors and/or particles from targeted surface1010 are on the outer region of the front sampling region and the intake(vacuum) ports are located on the interior region of the front samplingregion shown in FIG. 10C.

The chemical vapors and/or particles that are dislodged by an impingingair flow 1020 are suctioned with a return air flow 1022 into the intakeport 1018 in the center region of the sampling wand 1013 as a closedloop air current. The air jet ports 1015 and the intake port(s)administer the sheet-like impinging air flow 1020 and the return airflow 1022. The critical angle 1025 at which the impinging air flow 1020is impinging the targeted surface 1010 are between substantiallyperpendicular to substantially parallel toward the targeted surface 1010shown in FIG. 10B. There can be many different configurations where thefacing air jet arrays are located on the outer region of the wand andthe intake ports are on the interior region. The sheet-like impingingair flow 1020 can be administered from a long slit or an array of smallindividual opening ports, whereby a uniform surface area is completelyblanketed. Air jets ports 1015 can be configured with a single slit asshown in FIG. 10 or a plurality of the slits or array of single air jetscooperating in a fashion that could result in the same sheet-likeimpinging air flow 1020. The air jet ports 1015 do not necessarycompletely surround the front sampling region. As one dimension issignificant greater than the other, the jets may only be arranged alongthe longer dimension; as shown in FIG. 10C configuration I, the top andbottom jet slit may be removed if it does not reduce the samplecollection efficiency. In a variety of alternative embodiments, FIG. 10Cdepicts three possible configurations I-III, but the handheld wand'sconfigurations are not limited to these examples. Configuration I has asingle zone 1018 for the intake ports whereas configuration II has twozones 1018 for the intake ports. In configuration III, the intake portsare accompanied with pulsing jet ports 1051 that are all containedinside of the continuous flow jet ports on the outside of the frontsampling region. The pulsing jet ports generate jet like air pulses thatdirectly impinges on the targeted surface 1010 to assist in dislodgingthe chemicals from the surface. For all of the possible configurationsthe air jets (from ports 1015) located on the outer region of the frontsampling region may be a continuous flow or a pulsing air flow.

For collecting a sample from a human body, the temperature and pressureof the impinging flow will be carefully balanced and controlled. In thisdesign, a safety mechanism will be built in to control the electronics.The flow will automatically shut off when the temperature is over thepreset limit. The sample collection flow path will be built withchemical resistive material, e.g. Teflon, so that sample loss in theflow path will be minimized. With the consideration that the metal andtrace detector will be combined in the same handheld wand suitablematerials will be incorporated into the design. For example non-metalmaterials will be used for the entire front portion of the handheld wandwhen a metal detector is combined in the handheld wand. As shown in FIG.2A the metal detector coil 220 can be incorporated into the frontsampling region 212 of the handheld multi-function interrogatingapparatus.

A non-limiting example of a sampling event involves searching theselectee from a distance less than a half inch away from the targetedsurface with the handheld wand. A constant air flow is delivered to theimpinging ports. The temperature of this flow is controlled at slightlyhigher than human body temperature, e.g. 40-45.degree. C. As theimpinging flow on the outer layer of the clothing occurs, there arethree simultaneous effects that help in collecting residue explosives:a) the relatively high speed flow from the impinging jets could releaseparticles that are attached to the clothing, these loose particle cansubsequently be pumped into the suction slits; b) the relative highertemperature could evaporate some of the explosives into the gas phase,for example, the RDX vapor pressure increase from 6.0.times.10−3 ppb to0.1 ppb when temperature change from 25 to 43.degree. C.; the vapor ofexplosive will be pumped toward the preconcentrator and trapped on thismedia; c) as the higher pressure and temperature air penetrate throughthe fabric, it may cause a local high pressure inside the cloth, someportion of air from inside the clothing could be collected into theadjacent suction slits. The final sample releasing/collecting efficacyis the result from these three effects.

FIG. 4 illustrates the above discussed sampling mechanism. The crosssection view 403 represents half of the sampling handheld wand; theentire cross section 202 of this wand is shown in FIG. 2B. The impingingair flow 415, and the return (collection) flow 416, 418 is shown withthe particles 409 in the air current. When the handheld wand is appliedagainst clothing 410, the fabric can be described as in a “wave” shape,where the high point of the “wave” is created by the suction portscaused by the local low pressure; the low of the “wave” is create by theimpinging flow caused by the local high pressure air 412. As thehandheld wand is moved by the screener, the “wave” moves with it. Duringthis process, available explosive particles and/or vapors are collectedonto the sample collector of the handheld wand.

In a variety of embodiments, the dynamic inspection method shown in FIG.11A-C of sampling a human body comprises, moving the handheld wand 1113in a sweeping motion collecting any chemical vapor or particles 1101that may be on a persons clothing or skin 1110. The sweeping motion issimilar to using a brush to comb a person's hair, although different inthat the handheld wand does not contact the surface. Instead, thehandheld wand 1113 uses the impinging jets 1115 to dislodge the chemicalvapors and/or particles from the clothing or skin 1110 whereby theintake port 1118 collects them. The handheld wand 1113 will not contactthe clothing or skin 1110 of the person but instead will sample at adistance, e.g. ½ inch away from the clothing or skin 1120, preferablybetween not contacting the person and 2 inches away from the person'sclothing or skin. The wand could be used at any distance in which theimpinging air jets can dislodge the chemical vapors and/or particles.The handheld wand is configured such that the impinging jets 1115 andsufficient air flow rate are used to assure that movement of thedislodged particles are significantly faster compared to the sweepmotion during sampling, thus the speed of the sweep motion duringsampling does not affect the motion of the dislodged vapor and/orparticles in the return flow. In a sampling event, the handheld wand isused to sweep a human body dislodging chemical vapor or particles 1101that are located in the path of handheld wand's motion and subsequentlycollects these vapors or particles on a sample collector. The samplecollector which contains the vapor or particle is either manuallytransferred to a detector, or is arranged directly in fluidcommunicating with an onboard detector to desorb and detect the vaporsand/or particles from the sample collector. The above disclosed samplingmethod can also be applied to other surfaces that are not on a humanbody. Such a surface may include but not limited to, a handle of thesuitcase, interior surface of a suitcase, computer keyboard, packagingboxes, etc. The disclosed sampling method can also be an automatedmachine controlled sweeping that could satisfy the above describedsampling conditions.

The sampling/preconcentrating filter is one of the key elements ofbuilding a successful trace sampling wand. The particle sizes ofexplosive residues are in the range of submicron to several hundredmicrons. Knowledge learned from the trace detection portal system isthat larger explosive particles can be more effectively collected. Inaddition, the large particles represent a major portion of availablesamples. Therefore, the preconcentrating filter will be chosen tocollect particles from several to tens of microns in size. This approachcan practically reduce the load of sampling pump, thus a smallersampling pump could be used.

In addition, the sample desorption efficiency will also be consideredwhen selecting a filter for the sample collector. In commercial tracedetection systems, the thermal desorber does provide sufficient heat,fast enough to evaporate the explosives on the sample collector all atonce. Although the heat transfer between the sample collector anddesorber surface was slow. In this design, we use single or multiplelayers of filter material, such as metal screens in the right openingsize to preconcentrate explosives. Efficient heat transfer will resultin significant sensitivity improvement compared to currently availablesample collectors. If the trace sampling handheld wand had a comparablesampling efficiency as the current wiping wands, the trace samplinghandheld wand can potentially be used for not only people sampling, butalso on objects currently screened by the swabbing method.

For vapor sampling, the filters, such as metal screens will also becoated with a layer of affinitive material, such as modified PDMS usedfor SPME. Possible coating material may also include a functionalizedsurface, such as sol-gel. The sampling handheld wand may be made toreuse sampling materials that did not cause an alarm in the tracedetection systems. For the trace detection handheld wand, the samplecollector if it is necessary to preconcentrate the particles, will bereused until loss of collection efficiency occurs; the material is selfcleaned during each flash heating cycle.

In the case when the multi-function handheld wand does not contain anonboard detector for analysis of sampled chemicals, a sample collectorconsisting of a filter material that can withstand high temperaturessuch as but not limited to metal, Teflon, ceramic, etc. is manuallyinserted into the handheld wand before sampling the human body and thenwhen the sampling is completed, the sample collector is manually removedand inserted into a detection system for analysis. When sampling a humanbody for chemical vapors and/or particles, the clothing and skin thatare sampled from can also contain “dirty” particles such as lint, hair,crumbs, etc. (not limited to these) that gets collected on the filteralong with the desired chemical vapors and/or particles. These “dirty”particles are transferred into the detector as well when the filter'scontents are desorbed for analysis. With constant use it would only takea short amount of time for the detector to accumulate a large amount ofthese “dirty” particles and need to be serviced to rid the detector ofthese “dirty” particles. These “dirty” particles can also have thedesired chemical vapors and/or particles adhered to them, so removingthem from the filter before detector analysis would not be prudent.Keeping these “dirty” particles along with the chemical vapors and/orparticles on the filter can be accomplished by sandwiching the contentsof the collection between two surfaces such as plates, screens, filters,etc. (not limited to these). Keeping these “dirty” particles along withthe sample on a filter can not only be used for the interrogatingapparatus disclosed herein, but this method and concept can also be usedfor other devices.

In a variety of embodiments, this sample collector comprises (a) amovable screen that can be lock at positions where the sampling materialis covered or uncovered. The covered position is for transportingsample, desorbing and detecting samples from the sampling material, andthe uncovered position is for collection chemical vapors and/orparticles onto the sampling material; (b) a self locking mechanism thatlocks the movable screen in uncovered position in the handheld wandduring sampling and in covered position when removed from the handheldwand through transportation and detection. In a variety of embodiments,the sample collector comprises a sampling/preconcentrating material 1245where the chemical vapors and/or particles are trapped during thesampling of a human body and a movable screen 1215 that can bepositioned so that it covers the sampling/preconcentrating material orso that it does not obstruct the sampling/preconcentrating material 1245as shown in FIG. 12. Before using the sample collector, the moveablescreen assembly 1215 covers the sampling/preconcentrating surface, FIG.12A. When the sample collector is inserted into the handheld wand beforesampling, the moveable screen assembly 1215 slides away from thesampling/preconcentrating surface 1245 so that it is unobstructed. Aprotruding surface in the wand catches the hole/bump 1270 and slides themoveable screen until it is stopped by a ridge in the surface 1260.Sampling takes place with an unobstructed sampling/preconcentratingsurface configuration, FIG. 12B. When the sample collector is removedfrom the handheld wand, the moveable screen slides over thesampling/preconcentrating surface 1245 until it is stopped by a ridge inthe surface 1250. With the sample collector removed from the handheldwand the sampling/preconcentrating surface is covered by the movablescreen as shown in FIG. 12A and the movable screen is locked into placeby having the bumps overlap 1265. The sample collector is manuallyinserted into the detector and the contents are desorbed with themoveable screen covering the sampling/preconcentrating surface, FIG.12A. After analysis, and removal of the sample collector from thedetector, the moveable screen can be positioned so that the remaining“dirty” particles can be wiped off the sampling/preconcentrating surfaceand the sample collector can be re-used in another sampling event.

In a variety of embodiments, the sample preconcentrating surface 1245are made of multilayer diffusion bonded metal screens. Each layer of thescreen may have difference opening sizes. The multilayer samplepreconcentrator is intended to separate and collect particles ofdifferent size simultaneously without significantly increasing flowresistance during the sample collection process. The screens can be madeof, but not limited to, stainless steel, bronze, Monel, and other metalalloys. The opening of the screen may be in the range from sub-micronsto hundreds of microns.

In addition to releasing particles with only the impinging air flow,since certain explosive materials are inherently sticky, such as C-4 (aRDX based explosive), and Deltasheet (PETN based explosive) thetemperature of the air flow or the addition of a doping substance 1301into the airflow 1320 will assist in lifting and collecting theparticles of interest 1310 in the return airflow 1322 as shown in FIG.13. As discussed below, the doping substance can be in many forms andcan be added to one, a portion, any combination, or all of the airflowsfrom the interrogating apparatus. Due to their makeup, these explosivemolecules are generally greasy substances and are hydrophobic. Particlesof interest to this invention which are not explosive molecules can alsobe hard to remove from the targeted surface and the methods andapparatus disclosed below can be used not only for explosive molecules,but for particles in general. For the purpose of describing thesegeneral methods and the apparatus, explosive molecule examples will bediscussed.

As used herein, a “doping substance” is in the form of: vapor, droplets,an aerosol, liquid, organic solvent, solid, resin bead/s, polystyrenematrix, atom, molecule, compound, metal, alloy, or any other mobilemedium in which can be transported in an airflow. The use of a dopingsubstance to assist particle release from a targeted surface can notonly be used for the interrogating apparatus disclosed herein, but thismethod and concept can also be used for other devices.

It is also to be considered that the handheld wand can be used to sampleobjects besides people, in this case more flexible parameters could beused to release explosives from the surface. For example, thetemperature of the impinging air can be significant increased toevaporate the explosive in to the gas phase. The impinging air pressureand different sizes of the nozzles in the impinging jet array may beoptimized to achieve maximal particle removal and collection efficiency.

In a sampling event electrostatics (static electricity) can affect theability for the non-contact interrogation apparatus to collect theexplosive particles 1402 from the targeted surface 1401 as shown inFIGS. 14A-C. For example, when two non-conducting materials 1402 and1401 come into contact with each other, an adhesion is formed betweenthe two materials, FIG. 14A. Depending on the properties of thematerials, the adhering force between two materials may be caused by acharge imbalance. In order to neutralize the charge imbalance and lessenthe adhesion between materials, a low-resistance path for electron flowis provided. Water 1410 can be added as a doping substance to thesheet-like impinging air flow 1420 which lightly mists the targetedsurface neutralizing the charge imbalance shown in FIG. 14B. Thereforethe adhesion between materials is lessened as shown in FIG. 14C and theexplosive particle 1402 is collected more effectively. In addition towater, plasma (ionized air) can be used to remove static electricity,dust particles, and waxes. Ions and free electrons can be added as adoping substance to the sheet-like impinging air flow 1420 to neutralizethe charge imbalance between materials by bombarding them with a chargedspecies. The bombardment with ions and/or free electrons 1415 candislodge explosive particles 1402 from the targeted surface 1401 andthen be collected in the return air flow 1422 by way of the closed loopair current as shown in FIG. 14D.

Since explosive particles have molecular functionality which isdifferent from the matrix that is adhered to the targeted surface, adoping substance which selectively interacts with the explosive'sparticles functionality can help remove the explosive particle from thematrix as shown in FIG. 15A-B. A doping substance 1501 can be added tothe sheet-like impinging air flow which bombards the targeted surface1511 and hits the entrained explosive particle 1510 in the matrix 1502whereby the explosive particle 1510 attaches to the doping substance1501 forming a complex 1505 which is removed from the matrix 1502 bybouncing off the targeted surface 1511 into the intake port 1518 of theinterrogation apparatus 1513 by way of the closed loop air current 1508as shown in FIGS. 15A-B. The attachment of the explosive particle to thedoping substance is accomplished by utilizing intermolecularinteractions that are exclusive to the explosive molecule such as ionicinteraction, hydrogen bonding, dipole-dipole, and .pi.-.pi. An exampleof using hydrogen bonding as the intermolecular interaction is discussedbelow.

Many explosive molecules have a nitro-group functionality, such as RDX,which has three nitro functional groups. An interaction that can havesome selectivity and also be reversible is hydrogen bonding. Hydrogenbonding occurs when a hydrogen atom is covalently bonded to a smallhighly electronegative atom such as nitrogen, oxygen, or fluorine. Thehydrogen atom has a partial positive charge and can interact withanother highly electronegative atom in the explosive molecule. TheOxygen atoms in the nitro groups can participate in hydrogen bonding bybeing the hydrogen bond acceptor. The hydrogen bond donor could comefrom a number of sources; alcohols, phenols, thiols, amines, etc. Forexample, a doping substance such as a resin bead 1601 can have aplurality of reactive sites 1645 shown in FIG. 16A. It has been shownthat strongly acidic polymers, such asSXFA-[poly(1-(4-hydroxy-4-trifluoromethyl-5,5,5-trifluoro)pent-1-enyl)mehylsiloxane],bind to the basic lone pairs of the nitro groups. The strongly electronwithdrawing nature of the two adjacent trifluoromethyl groups to thealcohol group increase the hydrogen bond acidity and thereforeillustrate a stronger interaction. This alcohol group(hexafluoroisopropanol) 1630 can be chemically linked through covalentbond to a bead-like carrier, e.g. polystyrene matrix forming resin beads1601 and binds to the basic lone pairs of the nitro groups 1620 shown inFIG. 16B. In this case, resin beads 1601 are the doping substance thatis added to the sheet-like impinging air flow which bombards thetargeted surface.

When a large particle like doping substance, e.g. 2% cross-linked,200-400 mesh, 2 mmol N/g resin, or other solid matrix material (e.g.Teflon) is used in the interrogating apparatus's airflow, the largeparticle may enter the intake port of the interrogation apparatus by wayof the closed loop air current and may be deposited on the samplecollector. The mesh size of the preconcentrating filter would beadjusted to collect the doping substance. For example, these largeparticle like doping substances are doped into the impinging airflow,interact with the explosive on the targeted surface, return via thereturn flow, and are trapped on the sample collector. The trapped dopingsubstances can also collect vapor during the time they are trapped onthe collector. In a variety of embodiments using resin beads as thedoping substance, in addition to binding the explosive molecules by theinteraction through bombardment, the free reactive sites on thedeposited resin beads can interact with vapor that gets cycled throughthe closed loop air current, thus effectively collecting vapor on thesample collector.

In a broad sense, any doping substance which can be trapped on thepreconcentrating filter has the ability to collect vapor in the returnflow of the closed loop air current. A doping substance can have a layerof affinitive material, such as modified PDMS used for SPME or afunctionalized surface, such as sol-gel that can collect vapor.

Another use of a doping substance which is added into the airflow toassist in lifting and collecting the chemicals of interest is a dopingsubstance that may remove both the matrix and explosive moleculestogether. In order to separate the matrix 1702 and explosive molecules1710 from the targeted surface 1701, such as a fabric (found on luggageand clothing), a doping substance 1707 such as perchoroethylene, cyclicsilicone decamethylcyclopentasiloxane, and liquid CO.sub.2, but notlimited to these chemicals can be added to the air flow of theinterrogating apparatus as shown in FIGS. 17A-B. This process iseffectively the same as dry cleaning clothing and textiles using anorganic solvent other than water. The matrix 1702 and explosivemolecules 1710 are effectively removed from the targeted surface bysolvation into the doping substance 1707 when they come in contactforming a mixture 1730 that can be extracted by way of the closed loopair current 1708.

In addition to adding an organic solvent to remove and/or separate thematrix and explosive molecules from the targeted surface by way ofsolvation between liquids, a solid doping substance can be added to theair flow of the interrogating apparatus to interact with the matrix andexplosive molecule as shown in FIGS. 18A-B. An example of such a dopingsubstance are hydrophobic groups 1802, such as an alkane, alkene,benzene derivative, haloalkane, etc., that are chemically linked througha covalent bond to a peptide like carrier, e.g. polystyrene matrixforming resin beads, 1801. These resin beads are added to the sheet-likeimpinging air flow which bombards the targeted surface, picking up someof the matrix 1805 and explosive molecules 1810 forming a mixture 1808,and are collected into the intake port of the interrogation apparatus byway of the closed loop air current.

In another aspect of the invention the doping substance may contain oneor more metals and/or magnetizable materials therein as shown in FIGS.19A-B. As an example, the doping substance may be a polymer comprising ametal and/or a magnetizable material 1903, for instance, physicallyadmixed within the polymer 1905, or chemically combined with the polymer1919 (either internally, externally, or both). Resin beads or othersolid matrix material e.g. silicon, can have a magnetic componentchemically linked to a portion of the polymer matrix. For example, aniron complex linked to a portion of a Teflon bead would assist in thecollection of the Teflon beads if the particle sampling component of theinterrogating apparatus had the presence of a magnetic field. Theapplied magnetic field could be created by permanent magnets,electromagnets, or the like. Examples of metals that could be combinedwith the doping substance include, but are not limited to, lead,bismuth, cadmium, tin, indium, zinc, antimony, copper, silver, gold,iron, or the like.

The trace sampling wand design (size, general shape) may be used for thetrace detection handheld wand based on improved IMS, however severaldifferent apparatus configurations could be built based on the samplingmethod including, (a) adding a suitable IMS detector onboard: as the IMSis still the most versatile trace detector available for portableapplications, the device is aimed at having a trace detection handheldwand with a rugged, compact, high performance IMS inside the device; (b)The trace sampling handheld wand concept may be used with otherdetection methods. Besides the IMS detector, for different applications,other detection methods, such as florescent detectors, chemiluminescentdetector, will also be considered; (c) combining the sampling handheldwand with multiple detectors, such as a metal detector, will have addedbenefits by simplifying screening operations and removing intermediatesearching steps at check points.

A trace detection handheld wand can not only collect/preconcentrateexplosives, but also detect them in situ. The overall system size willincrease when an IMS based detector is included in the handheld wand;however, a novel IMS design that may significantly reduce the spacerequirement compared to conventional drift ring designs used by allcommercial IMS manufactures will be utilized. As shown in FIG. 5, theheight of the device will be adjusted to accommodate the detector 502.From a system design point of view, the detection handheld wand willonly include basic features for sampling, preconcentrating and detectingexplosives. There is no display or other user controls available on thedevice. However, the handheld wand can be reconfigured when it issitting on the docking station/charger 602 (shown in FIG. 6A). FIG. 6Bshows the difference between a sampling wand 606 and detection handheldwand 604. The sample trap dispenser and lock 609 are removed from thedetection handheld wand 604. More electronic control components will bepacked in the detection handheld wand.

The trace detection may be operated in operational modes, for example,if the search of interest is to find a specific location on the object,where the explosive or other chemicals are hidden, the handheld wandcould be operated in an online detection mode, it detects the chemicalswithout or a minimal preconcentration time while the handheld wand ismoving around the surface area. If the search of interest is to findwhether an individual or object is contaminated with the targetedchemicals, the handheld wand could be operated in a batch detectionmode, where it pre concentrates and detects the chemical with maximumsensitivity. As shown in FIG. 5, the detection result will be shown as“Red” or “Green” indication lights 508 besides the audible alarms; thealarm data could be sent to a remote computer or PDA via wirelesscommunication. In a variety of embodiments, the size of the detectionhandheld wand is 40L.times.10W.times.10H cm and weighs less than 3 lbs.The targeted size is estimated based on required sampling area,available sampling pump and anticipated detector size.

In a variety of embodiments, the handheld multi-function detection wand,with an onboard detector such as an ion mobility based detector (notlimited to only this particular detector), can be operated to performanalysis of chemicals from a surface in real time, such that there is nopreconcentration of chemical vapors and/or particles. During a samplingevent (a scan of potential threats), the chemical vapors and/orparticles are directly carried into the detector as they are beingsampled into return air flow. This instrument configuration andoperating method is useful for analysis of chemicals that may decomposewhile being thermally desorbed from the preconcentrating trap to thedetector and are therefore not correctly identified. Another advantagealready stated that this operation allows scanning for multiples threatssimultaneously, such as detecting chemicals and metal objects, andidentifying the exact location of the chemical on a subject whileconducting the inspection.

Shown in FIG. 9, when the handheld multi-function detection wand(interrogating apparatus) 900 incorporates an onboard chemical detector904 such as an ion mobility spectrometer, the samples test result can betransmitted to a computer or data terminal that connected to handheldwand. The connection can be either a wired or wireless. In case ofwireless connection, such as 802.11, IR, or Bluetooth, is used, theonboard wireless transmitter 906 and send data or command to a receiver908 housed in a computer terminal or PDA 910. The handheldmulti-function detection wand 900 will also incorporate a receiver 914whereby wireless communication from the computer terminal or PDA will bereceived. Wireless communications between devices can be through one ofseveral electromagnetic communications spectrums, includingradio-frequencies, microwave frequencies, ultrasound or infrared. Apositive detection result would have an audible alarm from the wand 900and computer terminal or PDA 910 as well as visual indicator lights suchas a red indicator. However, communications between wand 900 andreceiver 908 can also be one way, e.g., wireless data 916 from wand 900to receiver 908; and in such an embodiment the receiver 908 preferablyunderstands the communications protocols of data 916 to correctlyinterpret the data from the wand 900. Receiver 908 in this embodiment“listens” for data transmitted from wand 900. Receiver 908 thus mayfunction as a remote receiver stationed some distance (e.g., one or tensof feet or more) from wand 900. In this embodiment the datacommunication between the wand 900 and receiver 910 is preferably“secure” so that only a receiver with the correct identification codescan interrogate and access data from the wand 900. A positive detectionresult would result in a visual, sensory (vibration), or audible alarmto the computer terminal or PDA 910 whereby the sampler and person beingsampled are not aware of a positive detection, but would immediatelynotify a security person/s to take the appropriate actions. In thissituation the person being sampled is not aware that he or she has beenidentified and therefore would not flee or harm the sampler in any way.The handheld wand may also include a reading device that can read andtransmit the identification of the sampled subject, such reading device920 may include but not limited to barcode reader, Radio Frequency ID(RFID) reader. Also, the wand 900 may further comprise a GPS locationdevice incorporated into the wand so that the location of the wand 900and alarms could be identified and allocated at any time. The datareported by the handheld wand can also be incorporated with other testsresult either onboard or at remote computer using an integrated dataanalysis programs. Potential threats could be identify and confirmedusing multiple, yet orthogonal detection methods, such as but notlimited to millimeter wave, x-ray, quadrupole resonance, CT, terahertz,etc.

In a variety of embodiments of ion mobility based detector, a novelcompact resistance coil ion mobility spectrometer (RC-IMS) detector fortrace detection wand: The RC-IMS (U.S. Patent Application No.60/766,825) uses helical resistive material to form constant electricfields that is used to guide ion movements in a ion mobilityspectrometer. This drift tube for ion mobility spectrometer isconstructed with a non-conductive frame, continuous resistance wires, anion gate assembly, a protective tube, flow handling components, an iondetector assembly, and other components. The resistance wires arewrapped on the non-conductive frame which form coils in a round shape.The coil generates an even and continuous electric field that guide ionsthat drift through the ion mobility spectrometer.

The resistance wires are not only used to form an electric field, italso functions as the heating element to heat up the drift tube. The ionmobility spectrometer design controls drift tube temperature using theabove mentioned coil to maintain drift gas temperature and a separateheating element is used to preheat the drift gas before entering thedrift region. The drift gas is delivered directly inside the coil andpumped away from the gas exit on the protective housing. Thisconfiguration provides a robust ion mobility spectrometer that is simpleto build with lower thermal mass along the ion and drift gas path, thusallowing rapid temperature changes required by some applications. Insummary, the drift tube design enables an ion mobility spectrometer tobe built with lower weight, lower power consumption, lower manufacturingcost, and free of sealants that may out gas.

With the unique RC-IMS design, multiple coils could be used to constructa two dimensional IMS with the ions drift in both axial and radiusdirection. In this configuration, the inner coil has a voltage offsetfrom the outer coil. FIG. 7 shows some components that are related tothe two dimensional separation of the RC-IMS. In most of the IMS,reactant ions are generated in the ionization source and product ionsare formed in the reaction region. The ionization source and reactionregion normally have a similar size opening as the drift tube diameter,as shown in FIG. 7A. In the RC-IMS design, the ions are pushed out ofthe ionization source 701 through a much smaller opening 708 as shown inFIG. 7B. After entering the drift region, the ions will not only driftdown the drift tube, they are also pushed toward the coil under theeffluence of the electric field. Therefore, ions with different mobilityare detected on different Faraday detection rings, 710, 711, 712, 713,714, and 715 (FIG. 7C). The two-dimensional separation effect of thissimple spectrometer can improve the detector by specificity reducing thefalse alarm rate.

Non-radioactive ionization methods for the detector: The “ready to beimplemented” non-radioactive ionization source is the corona dischargedionization method which has been well studied. Most corona dischargeionization generates similar ionic species comparable with Ni63ionization methods. Suitable configurations of the corona ionizationsource can be implemented into the RC-IMS to be used for the tracedetection handheld wand. There are several newer concepts ofnon-radioactive ionization methods that will also be considered tointerface with the proposed IMS. For example, electron beam ionization.

FIG. 8 shows the apparatus of the ion mobility spectrometer with analternative embodiment of the sample preconcentration and desorption.Instead of the flat filter like preconcentrator as disclosed above, thepreconcentrator can be made from a single or plural layer of coils asshown in this figure. The coil could be made of any material that couldbe flash heated, e.g. resistive metal or alloy. The coil could be coatedwith chemicals that may have different affinities toward certain classesof chemicals, e.g. PDMS or modified PDMS. The coil is made with adesignated pitch size that could trap/filter out certain sizes of theparticles during preconcentration. Multiple coils could be made withdifferent pitch sizes to achieve multiple step filtrations of particlesof different sizes. Coils with smaller diameters can be arranged insidethe larger ones, either coaxial or with an offside. If the coil at theupper stream of the fluid is to be filtered has a bigger pitch then thedown stream ones, the larger particles can be filtered out first andthen the smaller ones in turn.

As shown in the apparatus in the FIG. 8, when the sample flow 803 entersthe preconcentrator chamber 810, it pass through the coils 815 (onlysingle layer of coil is shown) and then is pumped away with the flow804. The particles of different sizes are trapped on different layers ofthe coils. In general, the big pitch is made on the inside coils tocapture larger particles and a smaller pitch is made on the outer coilsto trap finer particles. The vapor sample can be trapped on any of thecoils when interacting with the coil surface. They could be trappedwithout any affinitive coating if the preconcentrator is at a relativelow temperature. During the sample preconcentration stage, valve 821 isclosed, 822 and 823 are opened to allow flow to pass in a designateddirection. In addition, the affinity layer coating material generallyhas higher electrical resistance compared to the coil material itself.Thus it can function as insulating layer when electrical current ispassing through the coil for flash heating. The coating could betemperature resistive polymers, such as PDMS, or any other material thathas a higher resistance than the material of the coil, functionalizedsilica based material is another example. Many sol-gel materials thatcould stand higher temperatures can also be coated on a metal coil afterthey are made into the right size and shape. Different coils ordifferent sections of the coil can be coated with different materials totrap chemicals of different classes.

During the desorption process, a local chemical environment can becreated to assist the desorption/evaporation process for the trappedsamples of interest. To build up the certain level of chemicalconcentration is the desorption area, in this figure it is thepreconcentration chamber 810, chemicals can be introduced as gas, liquidor solid as long as the chemicals can reach the trapped samples. Themost convenient way to introduce such chemicals is bring them in aschemical vapor. The function of these chemicals is either to directlyreact with the samples that have been trapped or as catalysts that canconvert the trapped sample into a form of interest. In addition, thesame effect may be achieved not by introducing additional chemicals, butchoosing right kind of material to build or coat the preconcentratorcoil. Under elevated temperature, the materials may behave as catalyststo achieve the same result of adding chemicals into the chamber.

To introduce additional chemicals to form a desired chemical environmentfor desorption, valve 822 is closed, 821 and 823 are open to redirectthe source of the desorption flow. Gas flow 802 that passes through achemical chamber 830 is introduced to the preconcentration chamber 810during the desorption process. Chemical vapors that formed in thechemical chamber 830 are brought to the preconcentrated samples (thatare trapped on the coils 815) to assist the desorption process. Duringthe desorption process, the coils 815 are flash heated with a controlledtemperature ramping speed to evaporate the trapped chemicals. In mostapplications, the doping chemicals through 821 are not needed for thedesorption process. In this case, the desorption gas flow can bedirected through 822. However, there are many thermal labile compoundsthat decompose before being evaporated to the gas phase. The doping ofchemicals through 821 is to create a chemical environment in thepreconcentrator chamber 810 to modify/control the reactions during thedesorption. The products of desorption and reactions are brought intothe detector for sub-sequential chemical analysis. The preconcentratorunit does not necessarily need to be used with an ion mobilityspectrometer 800 as shown in FIG. 8. It could be interfaced to otheranalytical methods, such as a mass spectrometer. Optionally, thechemical chamber 830 can also be connected to a separate desorber formanual thermal desorption of collected samples. In many samplecollection processes, the chemical can be preconcentrated on a filterpaper like subtract using different methods, such as wiping a surfacewith the sample trap. In this case, the assisting chemicals aredelivered to the thermal desorption heating plate chamber 840 via 824when the sample trap is insert into the desorber. Flow 805 can either begas outlet while the preconcentration chamber 810 is in use or gas inletduring a normal desorption process. In the later case, the assistingchemicals are not used and flow 803 is the purging flow for thespectrometer. As an example of the described trapping-desorption method,detection of peroxide based explosives is limited by the rapiddecomposition during the desorption process. Using the method describedin this invention, a clear decomposition path can be defined. Forexample, Hexamethylene Triperoside Diamine (HMTD) does not have asensitive response in IMS systems because of the thermal decomposition,however, if the explosive is desorbed in the modified chemicalenvironment that is doped with acidic vapor, a decomposition product canbe predicted. In this specific case, the product is peroxy-bis-methanol[Journal; Legler; CHBEAM; Chem. Ber.; 18; 1885; 3344] that could besensitively detected by IMS in the negative ion mode. As it could beachieved by the apparatus described in this invention, thermaldesorption of the trapped samples within chemically doped gasenvironment can be used to enhance desorption efficiency of thepreconcentrator for explosive analysis.

1. A non-contact interrogating apparatus comprising, a) a front samplingregion; b) more than one pair of facing air jet ports arranged in alinear array; the air jet ports form a sheet-like air flow that releasesand/or carries some sample from a targeted surface; c) at least somesample is collected at a intake port that is located between thesheet-like impinging air flow; and d) a critical angle of the sheet-likeair flow, which determines the standoff distance during sampling, suchthat the sheet-like air flow reaches the targeted surface before passingthe midpoint of the pair of facing air jet ports arranged in a lineararray, administering the sheet-like air flow and return air flow suchthat chemicals vapors and/or particles surrounded by the front samplingregion, sheet-like air flows, and the targeted surface are suctionedwith a return air flow into the intake port.
 2. The non-contactinterrogating apparatus of claim 1, wherein the critical angle issubstantially perpendicular to substantially parallel between thesheet-like impinging air flow and the targeted surface.
 3. Thenon-contact interrogating apparatus of claim 1, further comprises anonboard detector for analyzing a collected sample.
 4. The non-contactinterrogating apparatus of claim 3, wherein the onboard detector is anion mobility based detector.
 5. The non-contact interrogating apparatusof claim 1, further comprises a doping substance added to at least oneof the pair of facing sheet-like impinging air flows to assist theparticle release from the targeted surface.
 6. The non-contactinterrogating apparatus of claim 1, further comprises a samplecollector.
 7. The non-contact interrogating apparatus of claim 6,wherein the sample collector has a preconcentrator.
 8. The non-contactinterrogating apparatus of claim 6, wherein the sample collector has aheated filter.
 9. The non-contact interrogating apparatus of claim 6,wherein the sample collector has a movable screen.
 10. A dynamicinspection method, comprising: a) moving an interrogating apparatus in anon-contacting sweeping motion whereby one or more sweeps along atargeted surface area are performed for the targeted surface area; b)dislodging and collecting particles from the targeted surface area froma standoff distance controlled by the critical angle of the sheet-likeair flow, such that the sheet-like air flow reaches the targeted surfacebefore passing the midpoint of the pair of facing air jet ports arrangedin a linear array, administering the sheet-like air flow and return airflow such that chemicals vapors and/or particles surrounded by the frontsampling region, sheet-like air flows, and the targeted surface aresuctioned with a return air flow into the intake port, and c) detectingparticles with a detector.
 11. The dynamic inspection method as claimedin claim 10, wherein the interrogating apparatus is controlled by anautomated fashion.
 12. The dynamic inspection method as claimed in claim10, wherein the pair of facing airflows are either continuous or pulsed.13. The dynamic inspection method as claimed in claim 10, wherein thedetection is performed in real time with an onboard detector.
 14. Thedynamic inspection method as claimed in claim 10, which furthercomprises, preconcentrating particles on a sample collector.
 15. Thedynamic inspection method as claimed in claim 14, which furthercomprises, desorbing the particles from the sample collector into thedetector.
 16. The dynamic inspection method as claimed in claim 14,which further comprises, manually transferring the sample collector intoa stand alone detector.
 17. The dynamic inspection method as claimed inclaim 10, which further comprises, mixing at least one doping substanceinto the pair of facing air flows.
 18. The dynamic inspection method asclaimed in claim 10, which further comprises, heating the pair of facingair flows.
 19. The dynamic inspection method as claimed in claim 10,which further comprises, detecting a plurality of threatssimultaneously.
 20. The dynamic inspection method as claimed in claim10, which further comprises, identifying a threats location on anobject.